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New York Journal of Mathematics
Volume 28 (2022), 617-649

  

Neeraj K. Dhanwani, Kashyap Rajeevsarathy, and Apeksha Sanghi

Split metacyclic actions on surfaces

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Published: March 23, 2022.
Keywords: surface; mapping class; finite order maps; metacyclic subgroups.
Subject: Primary 57K20; Secondary 57M60.

Abstract
Let Mod(Sg) be the mapping class group of the closed orientable surface Sg of genus g ≥ 2. In this paper, we derive necessary and sufficient conditions under which two torsion elements in Mod(Sg) will have conjugates that generate a non-abelian finite split metacyclic subgroup of Mod(Sg). As applications of the main result, we give a complete characterization of the finite dihedral and the generalized quaternionic subgroups of Mod(Sg) up to a certain equivalence that we will call weak conjugacy. Furthermore, we show that any finite-order mapping class whose corresponding orbifold is a sphere has a conjugate that lifts under certain finite-sheeted regular cyclic covers of Sg. Moreover, for g ≥ 5, we show the existence of an infinite dihedral subgroup of Mod(Sg) that is generated by an involution and a root of a bounding pair map of degree 3. Finally, we provide a complete classification of the weak conjugacy classes of the non-abelian finite split metacyclic subgroups of Mod(S3) and Mod(S5). We also describe nontrivial geometric realizations of some of these actions.

Acknowledgements

The first and third authors were supported by the UGC-JRF fellowship. The authors would also like to thank Dr. Siddhartha Sarkar for helpful discussions.


Author information

Neeraj K. Dhanwani:
Department of Mathematics
Indian Institute of Science Education and Research Mohali
Knowledge city, Sector 81, Manauli, PO, Sahibzada Ajit Singh Nagar
Mohali 140306, Punjab, India

neerajk.dhanwani@gmail.com

Kashyap Rajeevsarathy:
Department of Mathematics
Indian Institute of Science Education and Research Bhopal
Bhopal Bypass Road, Bhauri
Bhopal 462 066, Madhya Pradesh, India

kashyap@iiserb.ac.in

Apeksha Sanghi:
Department of Mathematics
Indian Institute of Science Education and Research Bhopal
Bhopal Bypass Road, Bhauri
Bhopal 462 066, Madhya Pradesh, India

apeksha16@iiserb.ac.in